Health officials are monitoring more than 200 people who may have been exposed to Ebola in southern Nigeria and are working to find more people at risk in a race to contain the disease's spread in Africa's most populous country.
Authorities had been cautiously optimistic that they would be able to keep Nigeria's outbreak relatively small. The sick Liberian-American who brought the disease to Nigeria by plane was quickly isolated and officials said they were successfully monitoring the people who were in contact with him.
But then last month, one of those contacts escaped surveillance and fled to the southern oil hub of Port Harcourt. He infected a doctor who, in turn, exposed dozens of people to the disease when he continued treating patients after he began having Ebola symptoms, the World Health Organisation (WHO) has said.
Elsewhere in West Africa, the outbreak is spinning out of control, killing about 1,900 people so far, according to the WHO. Guinea, Liberia and Sierra Leone have each recorded hundreds of deaths and the disease most recently spread to Senegal.
In southern Nigeria, 200 people have been identified as having been exposed to the ill doctor and are being monitored, the WHO said. About 60 of those are considered at a high risk of getting Ebola.
Officials are urgently tracking down more contacts and educating residents about the disease, Dr Sampson Parker, the health commissioner for Rivers State, where Port Harcourt is located, said.
Rumour, fear and confusion about Ebola, which is more typically found in Central Africa, have helped to fuel its spread. Some people hide their symptoms or avoid medical care, seeing hospitals as places where people simply go to die.
Nigerian officials have urged people in Port Harcourt not to panic. Joseph Obari, an oil worker, said he felt the local authorities had put in place adequate measures to curtail the disease. But others worry that Ebola will spread.
"I am very afraid because of the manner the disease is spreading," said Oji Egwuno, a hotel manager in Port Harcourt. "I have to be cautious because I don't want to be the next victim."